D40 vs D50

D50 is 1.1 times as stiff as D40. It is 1.1 times as dense. Per unit mass they are about equally stiff (19.7 and 18.92 MJ/kg). Strength: f_m,k = 40 MPa for D40, f_m,k = 50 MPa for D50.

D40 EN 338:2016 D50 EN 338:2016

Side by side

ratio = D50 / D40 · log scale

Property	D40	D50	Unit	Ratio
E₁ Modulus, direction 1	13	14	GPa	1.08×
E₂ Modulus, direction 2	0.87	0.93	GPa	1.07×
E₃ Modulus, direction 3	0.87	0.93	GPa	1.07×
G₁₂ Shear modulus 1-2	0.81	0.88	GPa	1.09×
G₁₃ Shear modulus 1-3	0.81	0.88	GPa	1.09×
E₀,₀₅ Modulus parallel to grain, 5 % fractile	10.9	11.8	GPa	1.08×
ρ Density	660	740	kg/m³	1.12×
ρ_k Density, characteristic (5 % fractile)	550	620	kg/m³	1.13×
f_m,k Bending strength	40	50	MPa	1.25×
f_t,0,k Tension parallel to grain	24	30	MPa	1.25×
f_t,90,k Tension perpendicular to grain	0.6	0.6	MPa	1×
f_c,0,k Compression parallel to grain	27	30	MPa	1.11×
f_c,90,k Compression perpendicular to grain	5.5	6.2	MPa	1.13×
f_v,k Shear strength	4.2	4.5	MPa	1.07×
E/ρ Specific stiffness E/ρ · derived	19.7	18.92	MJ/kg	0.96×
c₀ Bar wave speed √(E/ρ) · derived	4438	4350	m/s	0.98×
f/ρ Specific strength f/ρ · derived	60.61	67.57	kJ/kg	1.11×

Values at the first thickness band or product form of each material (EN 338:2016; EN 338:2016). A minimum and a characteristic value are not the same kind of number — read the ratio as a guide. Each material's page lists every band and every source.